Nearly all systems using a gas supply need the utility to which the gas is being supplied to have a regulator. The function of the regulator is to prevent wide variations in the pressure being supplied and in particular to shut off the supply if the pressure is too high. A regulator is especially needed when the source of the gas is a container in which gas is stored at high pressure to ensure that excessive pressure will not be experienced within a utility connected to the container.
FIGS. 1 and 2 of the accompanying drawings illustrate a known regulator respectively in the valve-open and the valve-closed position. A housing 10 has a through bore 11 in which a tubular valve member 12 is moveable. The valve member has an enlarged upper end 13 which, in the valve-open position of FIG. 1, abuts against a shoulder 14 in the bore 11. Surrounding the lower end of the valve member 12 within the bore 11 is an adjustment cylinder 15. This is axially moveable by a nut 16 engaging screw threads in a lower portion of the bore 11 to adjust the loading of a spring 17 in compression between the undersurface of the enlargement 13 and the cylinder 15. The housing 10 has a lateral inlet 18 for connection to a source of gas under pressure (not shown) such as a canister of compressed air. The upper end of the bore 11 provides an outlet 19 for connection to a utility (not shown) such as a paintball gun to which compressed air is to be supplied from the canister.
Gas pressure at the outlet 19 acts on the surface of the enlargement 13 of the valve member presented toward the outlet to tend to move the valve member 12 to the valve-closed position of FIG. 2, thereby increasing the loading of the spring 17. In the fully valve-closed position of FIG. 2 the end surface 20 of the valve member 12 remote from the enlargement 13 comes into contact with a central plug 21 of the adjustment facility 15,16, thereby closing off communication between the inlet 18 and the through passage 22 of the valve member 12. Thus if the supplied gas pressure exceeds a value which is set by adjustment of the nut 16 the valve will close, but as soon as pressure at the outlet 19 falls below that value the valve will be opened by the spring 17.
A disadvantage of this prior art regulator is that the valve member 12 is under the influence of gas pressure acting on its end surface 20 counter to pressure acting on its enlarged end 13 and tending to keep the valve member in the valve-open position. In conditions of extreme pressure variation this can lead to a phenomenon known as “spiking” or “shunting”. In general the regulator is less sensitive to pressure variation than is desirable because of the counter force to which the valve member 12 is subject only when in the valve-open position.
A principal object of the present invention is to address this problem.